If you launch the game and the game is only showing part of the actual screen, you'll need to go into your properties for the game and select where it says Override high DPI Scaling Behavior and ensure it is selected.
For our steam users, you'll right click WWII Online, go to Properties,
then go to Local Files.
From here, right click on WW2.exe and choose Override High DPI Scaling Behavior.
This should resolve the issue and return your screen to normal size.